The syntheses of a series of novel ester-linked derivatives of the icosahedral [closo-B12(OH)12]2- boron cluster (closomer esters) are described using several synthetic methods. The reaction of bis(tetrabutylammonium)-closo-dodecahydroxy-dodecaborate, [NBu4]2 1, with carboxylic acid chlorides and anhydrides, vinyl esters with a Y5(OiPr)13O catalyst and 1,1'-carbonyldiimidazole-activated carboxylic acids yields the corresponding dianionic dodeca-ester ...

Fatty acid ethyl esters are secondary metabolites produced by Saccharomyces cerevisiae and many other fungi. Their natural physiological role is not known but in fermentations of alcoholic beverages and other food products they play a key role as flavor compounds. Information about the metabolic pathways and enzymology of fatty acid ...

Lipase-catalyzed synthesis of sorbitol-fatty acid esters was performed in eutectic media with extremely high substrate concentrations. Homogeneous eutectic melts of sorbitol and fatty acids of C6-C16 were prepared using an adjuvant mixture. Enhanced homogeneity of mixtures was confirmed by X-ray diffraction analysis. The substrate concentration was 3.63-6.67 M in the ...

A new generation of triazine-based coupling reagents (TBCRs), designed according to the concept of "superactive esters", was obtained by treatment of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium (DMTMM) chloride with lithium or silver tetrafluoroborate. The structure of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium tetrafluoroborate was confirmed by X-ray diffraction. Activation of carboxylic acids by using this reagent proceeds via triazine ...

Hydrogen-bonded networks composed of guanidinium (G) and 1,5-naphthalenedisulfonate (NDS) have been developed for the selective inclusion and separation of fatty acid esters based on their degree of unsaturation. Porous crystalline networks have been synthesized and include fatty acid esters during crystallization from both methanol and 2-methoxyethanol. Crystalline networks formed in ...

MGS0039 (3-(3,4-dichlorobenzyloxy)-2-amino-6-fluorobicyclo-[3.1.0]hexane-2,6-dicarboxylic acid) has been identified as a potent and selective antagonist for metabotropic glutamate receptors. However, the oral bioavailability of MGS0039 is 10.9% in rats, due to low absorption. Several prodrugs, synthesized to improve absorption, exhibited 40 to 70% bioavailability in rats. This study investigated in vitro metabolism using ...

A new sucrose ester, acretoside, has been isolated from the roots of the Greek endemic species Aristolochia cretica and identified as 6-O-p-coumaroyl-beta-D-fructofuranosyl-(2 --> 1)-alpha-D-glucopyranoside (1). In addition, a known sucrose ester, identified as arillatose B, two phenylpropanoid glucose esters, and five derivatives of aristolochic acids have been isolated. Their structures ...

Bacterial lipoproteins/peptides are composed of di-O-acylated-S-(2,3-dihydroxypropyl)-cysteinyl residues N-terminally coupled to distinct polypeptides, which can be N-acylated with a third fatty acid. Using a synthetic lipopeptide library we characterized the contribution of the lipid portion to the TLR2 dependent pattern recognition. We found that the two ester bound fatty acid length ...

The oxidation products of selenomethionine (SeMet) have been studied via experimental (77)Se NMR and theoretical (77)Se chemical shifts. Four signals are observed: a diastereomeric pair of selenoxides at 840 ppm and two unidentified resonances at 703 and 716 ppm. Theoretical DeltaG and chemical shifts suggest the 703 and 716 ppm ...

Six novel selenium-containing polyphenolic acid esters were synthesized and evaluated as antioxidants and 5-lipoxygenase inhibitors. Synthesis of the title compounds involved the Mitsunobu reaction of polyphenolic acids with 2-phenylselenoethanol. Compounds and were found to be very effective antioxidants and 5-lipoxygenase inhibitors with activity comparable to or better than caffeic acid ...

An efficient biocatalytic method has been developed for the conversion of (5S)-4,5-dihydro-1H-pyrrole-1,5-dicarboxylic acid, 1-(1,1-dimethylethyl)-5-ethyl ester (1) into the corresponding amide (5S)-5-aminocarbonyl-4,5-dihydro-1H-pyrrole-1-carboxylic acid, 1-(1,1-dimethylethyl)ester (2), which is a critical intermediate in the synthesis of the dipeptidyl peptidase IV (DPP4) inhibitor Saxagliptin (3). Candida antartica lipase B mediates ammonolysis of the ester ...

The effects of the number of fatty acid residues (n) in decaglycerol fatty acid esters, i.e., decaglycerol laurates (abbreviated to (C11)nG10), on the phase behaviors of three laurate esters, (C11)1.9G10, (C11)2.7G10, and (C11)3.4G10, were investigated. The unreacted decaglycerol remaining in each ester was removed by liquid extraction before use. (C11)1.9G10 ...

Small molecule mGluR1 enhancers based on the lead compound (9H-xanthene-9-carbonyl)-carbamic acid butyl ester derived from random-screening hit diphenylacetyl-carbamic acid ethyl ester were designed and synthesized as useful pharmacological tools for the study of the physiological roles mediated by mGlu1 receptors. The synthesis and the structure-activity relationship of this new class ...

Herein we report the design of a direct and continuous fluorometric assay for determining tissue transglutaminase (TGase) activity. The progress of the TGase-catalyzed reaction of 4-(N-carbobenzoxy-l-phenylalanylamino)-butyric acid coumarin-7-yl ester was monitored as an increase of fluorescence (lambda(exc) 330 nm, lambda(em) 460 nm) due to the release of 7-hydroxycoumarin. Using this ...

This work describes a rapid and high yielding oxidation of 14 tryptophanylated amino acid methyl esters to the corresponding 3a-hydroxypyrrolo[2,3-b]indoline (Hpi) amino acids with generally facile separation of syn-cis and anti-cis diastereomers. Structural X-ray diffraction data are presented for both diastereomers of Tr-Hpi-Gly-OMe, which allow for a putative assignment of ...

Carboxylesterases are among the best characterized prodrug-hydrolyzing enzymes involved in the activation of several therapeutic carbamate and ester prodrugs. The broad specificity of these enzymes makes them amenable for designing prodrugs. Porcine liver carboxylesterase 1 specificity for amino acid esters of three nucleoside analogs [floxuridine, gemcitabine, and 2-bromo-5,6-dichloro-1-(beta-D-ribofuranosyl) benzimidazole] was ...

LBT-999 (8-((E)-4-fluoro-but-2-enyl)-3beta-p-tolyl-8-aza-bicyclo[3.2.1]octane-2beta-carboxylic acid methyl ester), a cocaine derivative belonging to a new generation of highly selective dopamine transporter (DAT) ligands, and its corresponding carboxylic acid derivative, the latter used as precursor for labelling both with tritium and the positron-emitter carbon-11 (half-life: 20.38 min), were synthesized from (R)-cocaine. [(3)H]LBT-999 (>99% radiochemically ...

Although cleavable detergents were first synthesized a number of years ago, they have only recently been successfully applied to problems involving biological molecules. Recent reports have demonstrated that these compounds are useful for applications involving both 2D PAGE and mass spectrometry. However, most cleavable surfactants have utilized acid-labile functional groups ...

The aim of this work was to find an optimal ester group for preparation of lupane derivatives connecting high cytotoxicity with good chemical and pharmacological properties. Activities of methyl-, pivaloyloxymethyl- (Pom-), and acetoxymethyl- (Acm-) esters were compared with the activity of free acids. Although the methyl- and Pom-esters were generally ...

Jojoba wax is a natural gum base used as a food additive in Japan, and is obtained from jojoba oil with a characteristically high melting point. Although the constituents of jojoba oil have been reported, the quality of jojoba wax used as a food additive has not yet been clarified. ...

In 2002 several hundred people were taken ill after eating self-harvested brown crabs (Cancer pagurus) in the southern part of Norway. The symptoms were similar to diarrhetic shellfish poisoning (DSP) although with a somewhat delayed onset. This happened at the same time as an unusual early bloom of Dinophysis acuta ...

[reaction: see text] Addition of the enolate of tert-butyl acetate to cyanamide methyl ester 17 followed by treatment with LHMDS afforded vinylogous urea 19 in 27% yield. Vinylogous urea 19 was also obtained from 37 and tert-butyl cyanoacetate in 50% yield. Acylation of 19 with acid chloride 31d, followed by ...

Phytopathogenic fungi penetrate plants by breaking down the cuticular barrier with cutinase. Cutinases are extracellular hydrolytic enzymes that degrade cutin, a polyester composed of hydroxy and epoxy fatty acids. Until now, cutinase has been recognized by its ability to release labeled cutin monomers or by a non-specific esterase assay based ...

Fatty acid steryl esters (FASE) in whole meal of 14 genotypes of tetraploid wheats (Triticum dicocconand T. durum) and 17 genotypes of hexaploid wheats (T. spelta and T. aestivum) were analyzed using different chromatographic strategies. By both GC-FID and HPLC-ELSD, tetraploid wheats are lacking two major peaks. The amounts of ...

An improved synthesis of the precursor acetic acid-piperidine-4-yl ester by acetylation of 4-hydroxypiperidine hydrochloride in anhydrous chloroform was developed. A procedure for fast evaluation and characterization of products originated by acetylation of the 4-piperidinol using LC-APCI/MS with an acetonitrile-water gradient method on a Merck Purosphere RP-18 column was also developed. ...

A series of prodrugs of zidovudine has been synthesized in an effort to enhance spectrum of chemotherapeutic properties for the effective treatment of HIV/AIDS. The 5'-OH function of zidovudine was esterified with ciprofloxacin, norfloxacin, isoniazide, pyrazinamide acetic acid. The anti-HIV-1 activity of the esters was determined in CEM cell-line and ...

Enacyloxin IIa methyl ester in non-protic solvent gave rearranged product in acidic conditions such as surface of TLC plate of silica gel or by treatment with a catalytic amount of p-toluenesulfonic acid. On the other hand, such a rearrangement did not occur in polar protic solvent. The structure of the ...

Several new 4-amino-6,7-diphenylbicyclo[2.2.2]octane derivatives, methylthiosemicarbazones of bicyclo[2.2.2]octan-2-ones and esters of bicyclo[2.2.2]octan-2-ols were prepared. Their antitrypanosomal activities against Trypanosoma brucei rhodesiense (STIB 900) and their antiplasmodial activity against the K1 strain of Plasmodium falciparum (resistant to chloroquine and pyrimethamine) were investigated using microplate assays. In addition to that, the cytotoxicity of ...

The p-[N,N-bis(2-chloroethyl)amino]phenylacetic acid esters of hecogenin and aza-homo-hecogenin have been prepared and their antineoplastic activity was evaluated against two basic drug screening systems in rodents, P388 lymphocytic and L1210 lymphoid murine leukemias. Among the compounds tested, the p-[N,N-bis(2-chloroethyl)amino]phenylacetic acid ester of aza-homo-hecogenin was appeared to possess a significant higher antileukemic ...

Dehydroabietic acid derivatives have been reported to display antisecretory and antipepsin effect in animal models. Some 19 dehydroabietic acid diterpenes were prepared and assessed for gastroprotective activity in the HCl/EtOH-induced gastric lesions in mice as well as for cytotoxicity in human lung fibroblasts (MRC-5) and human epithelial gastric (AGS) cells. ...

Flavonoids including tea catechins and gallic acid esters were characterized for their ability to inhibit o-methyltranslation of protocatechuic acid (PCA) to form vanillic acid (VA) in rat liver cytosolic preparations and cultured hepatocytes. Flavonols and flavones exhibited different behaviors in inhibiting the formation of VA between the cell-free enzymatic preparations ...

Until recently, little focus was given to the presence of diarrhetic shellfish poisoning (DSP) toxin esters in seafood products. However, during the last few years, the occurrence of a high percentage of esters of the total amount of DSP toxins present in some seafood products has been observed. Samples of ...

The antitumour properties of two fatty acid esters of maltotriose, 6''-O-dodecanoylmaltotriose and 6''-O-palmitoylmaltotriose, in which the 6-OH at the non-reducing end of the maltotriose has been regioselectively acylated, were studied. Both compounds were synthesized by transesterification of vinyl laurate or vinyl palmitate with maltotriose, in the presence of immobilized lipase ...

The esters of Hecogenin and aza-homo-Hecogenin with N,N-bis(2-chloroethyl)aminocinnamic acid isomers have been prepared and their cytogenetic studies of structure-biological activity relationship were evaluated. The cytogenetic effects (sister chromatid exchanges (SCEs) induction and proliferation rate indices (PRIs) depression) by o-, m- and p-[N,N-bis(2-chloroethyl)amino] cinnamic acid were also investigated. Among the above ...

[structure: see text] An ester dienolate [2,3]-Wittig rearrangement was utilized to access the alkylated citric acid skeleton 6 that is characteristic for the viridiofungins and other members of the alkyl citrate family of secondary natural products. The [2,3]-sigmatropic rearrangement of (Z,Z)-15 provided the rearrangement product (+/-)-syn-16 in moderate yield and ...

[(Methyl-pyridin-2-ylmethyl-amino)-methyl]-phosphonic acid is a new bifunctional chelator for the fac-[(99m)Tc(CO(3))](+) core which can be linked to biomolecules via formation of phosphonic acid esters. Its synthesis and the coupling to model alcohols and to a bioactive molecule (cobinamide) are described. The rhenium complexes [Re(CO)(3)L] of the esters have been prepared and ...

A novel approach for measuring phytase activity is presented. We have developed a new chromophoric substrate analog of phytic acid, 5-O-[6-(benzoylamino)hexyl]-d-myo-inositol-1,2,3,4,6-pentakisphosphate that permits direct measurement of the phosphate ester bond-cleavage reaction using HPLC. This compound, along with its dephosphorylated T-phosphatidylinositol intermediates, are quantified using reversed phase chromatography with UV detection.

Coumarins, 4-hydroxycoumarins, and 4-hydroxyquinolin-2(1H)-ones can be conveniently prepared by treatment of alpha-halocarboxylic acid esters of salicylaldehyde, o-hydroxyacetophenone, methyl salicylate, and methyl N-methyl- or N-phenylanthranilates with sodium or lithium telluride. Phenylketene formation competes with cyclization of the alpha-chlorophenylacetate ester of methyl salicylate as demonstrated by a trapping experiment with benzylamine. Elemental ...